The present invention is directed to a dual layer papermaking fabric which provides even drainage throughout and in which both the paper support surface and the machine contact surface are weft dominant surfaces.
Normally, dual layer papermaking fabrics are woven with a single set of warp threads, upper layer weft threads and lower layer weft threads. Normally, the number of upper layer weft threads is twice that of the lower layer weft threads. It is also desirable to have long weft floats on the paper support surface to provide a smooth surface with adequate permeability. The machine contact surface also preferably comprises long weft floats for adequate permeability and for protecting the warp threads from wearing through contact with the machine rolls.
Papermaking fabrics developed with these features in mind are disclosed in U.S. Pat. Nos. 4,739,803; 4,709,732; 5,025,839; and 5,555,917.
The instant invention has for its object, a papermaking fabric having a paper support surface which is smooth so as to reduce fabric marking on the paper to a minimum.
Another object of the invention is a papermaking fabric having a stable paper support surface providing that the minimum of markings are uniform.
Another object of the invention is providing a papermaking fabric having a minimum of exposure for the warp threads on the outer fabric surfaces providing for increased wear and improved uniformity.
Another object of the invention is a papermaking fabric which maintains even drainage throughout.
Another object of the invention is a papermaking fabric having stabilized machine direction inner floats.
Another object of the invention is a papermaker's fabric having stabilized cross machine direction floats.
Another object of the invention is providing a papermaking fabric in which the warp cross-overs on the paper support surface and the warp cross-unders on the machine contact surface are arranged in diagonal rows across the fabric forming a balanced weave having a twill on each surface.